For management of a microbiological quality of raw materials, intermediates, and final products of drugs and medicines, the manufacturers of medicinal chemicals are obligated to measure the number of cells of microbes (bacteria and true fungi) included in them according to the Standards of Japanese Pharmacopoeia (JP) prescribed by the Ministry of Health, Labour and Welfare in Japan.
As a method for cell number measurement, a culture method is generally adopted in which the number of colonies (Colony Forming Units: CFUs) formed through cultivation for a certain period is visually measured. Because about one week is required as the cultivation period, waiting for results of cell number measurements by a quality management department is entailed in each of the following phases: raw material reception, intermediate production, and final product shipment. This has imposed inordinate economic burdens on the manufacturers.
As a measurement method that is faster than a culture method, An ATP (Adenosine TriPhosphate) luminometric assay is known.
The ATP luminometric assay is a method that measures luminescence generated by reacting ATP extracted from within microbes living in a sample with a luminescent reagent by a photodetection unit such as a photomultiplier tube and estimates the number of living cells from a quantity of luminescence thus measured (refer to Nonpatent Literature 1). A sample container is placed close to a photodetection unit and measurement is performed. Hence, luminescence derived from a single discrete container may sometimes be detected, which was not detected by a commonly used luminometer apparatus whose structure and sensitivity are not enough to detect it.
In an analysis method by luminometric detection, after preserving sample containers under a light shielding environment, it has heretofore been practiced to repeat a process of measuring a background noise which is luminescence derived from sample containers and selecting sample containers making a low background noise (Refer to, e.g., Patent Literature 1).
Besides, a quantity of ATP per bacterium is extremely small as compared with a quantity of ATP included in a large cell of a true fungus, human, etc. Hence, when a microbial contamination or ATP contamination occurs with incursion of a substance derived from a worker or an external environment into the luminometer apparatus, a quantity of ATP derived from bacteria is over-estimated.
To prevent a microbial contamination or ATP contamination, it is known that it is advisable to carry out a process including pretreatment of microbes and luminescence measurement, enveloped by a clean space such as a safety cabinet. To enhance the accuracy in measuring a quantity of ATP derived from bacteria, it is required to confine a space where the luminometer apparatus is used within such a clean space. Taking practical working operability into account, it is required to downsize the luminometer apparatus that is able to automatically carry out every process without intervention of a worker in any process, so that the apparatus can be installed inside a safety cabinet.
For example, Patent Literature 2 describes an automatic chemical analysis apparatus in which a reagent holder is installed inside a reaction disk having a plurality of reaction tubes installed therein. Also, Patent Literature 3 discloses an analysis apparatus equipped with a reagent disk, a member holding a sample dispensation chip and a reaction container, and a mechanism carrying the sample dispensation chip and the reaction container.